Ping.
https://gcc.gnu.org/ml/gcc-patches/2015-04/msg01434.html
Thanks,
Kyrill
On 23/04/15 17:57, Kyrill Tkachov wrote:
[resending due to mail client messing up.]
Hi all,
The EON instruction can be expressed either by (xor (not a) b) or (not (xor
a b)),
simplify-rtx canonicalizes to the second form and we have a pattern for it
(*xor_one_cmpl<mode>3) but we don't have a pattern for the shifted operand
version. This patch adds that pattern as well as the proper handling of it
in
aarch64_rtx_costs. The zero-extend version of it is also added.
While we're in the NOT case of rtx costs this patch also
corrects the costing of MVN+shift operations.
With this patch, for C code:
unsigned long
baz (unsigned int a, unsigned int b)
{
return ~(a ^ (b << 6));
}
unsigned long
foo (unsigned long a, unsigned long b)
{
return ~(a ^ (b >> 24));
}
we now generate:
baz:
eon w0, w0, w1, lsl 6
ret
foo:
eon x0, x0, x1, lsr 24
ret
instead of the previous:
baz:
eor w0, w0, w1, lsl 6
mvn w0, w0
uxtw x0, w0
ret
foo:
eor x0, x0, x1, lsr 24
mvn x0, x0
ret
Bootstrapped and tested on aarch64-linux.
Ok for trunk?
Thanks,
Kyrill
2015-04-23 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* config/aarch64/aarch64.md
(*eor_one_cmpl_<SHIFT:optab><mode>3_alt):
New pattern.
(*eor_one_cmpl_<SHIFT:optab>sidi3_alt_ze): Likewise.
* config/aarch64/aarch64.c (aarch64_rtx_costs): Handle MVN-shift
appropriately. Handle alternative EON form.
